lnd

type BreachConfig struct {
	// CloseLink allows the breach arbiter to shutdown any channel links for
	// which it detects a breach, ensuring now further activity will
	// continue across the link. The method accepts link's channel point and
	// a close type to be included in the channel close summary.
	CloseLink func(*wire.OutPoint, htlcswitch.ChannelCloseType)

	// DB provides access to the user's channels, allowing the breach
	// arbiter to determine the current state of a user's channels, and how
	// it should respond to channel closure.
	DB *channeldb.DB

	// Estimator is used by the breach arbiter to determine an appropriate
	// fee level when generating, signing, and broadcasting sweep
	// transactions.
	Estimator lnwallet.FeeEstimator

	// GenSweepScript generates the receiving scripts for swept outputs.
	GenSweepScript func() ([]byte, error)

	// Notifier provides a publish/subscribe interface for event driven
	// notifications regarding the confirmation of txids.
	Notifier chainntnfs.ChainNotifier

	// PublishTransaction facilitates the process of broadcasting a
	// transaction to the network.
	PublishTransaction func(*wire.MsgTx) error

	// ContractBreaches is a channel where the breachArbiter will receive
	// notifications in the event of a contract breach being observed. A
	// ContractBreachEvent must be ACKed by the breachArbiter, such that
	// the sending subsystem knows that the event is properly handed off.
	ContractBreaches <-chan *ContractBreachEvent

	// Signer is used by the breach arbiter to generate sweep transactions,
	// which move coins from previously open channels back to the user's
	// wallet.
	Signer input.Signer

	// Store is a persistent resource that maintains information regarding
	// breached channels. This is used in conjunction with DB to recover
	// from crashes, restarts, or other failures.
	Store RetributionStore
}

type ContractBreachEvent struct {
	// ChanPoint is the channel point of the breached channel.
	ChanPoint wire.OutPoint

	// ProcessACK is an error channel where a nil error should be sent
	// iff the breach retribution info is safely stored in the retribution
	// store. In case storing the information to the store fails, a non-nil
	// error should be sent.
	ProcessACK chan error

	// BreachRetribution is the information needed to act on this contract
	// breach.
	BreachRetribution *lnwallet.BreachRetribution
}

type NurseryConfig struct {
	// ChainIO is used by the utxo nursery to determine the current block
	// height, which drives the incubation of the nursery's outputs.
	ChainIO lnwallet.BlockChainIO

	// ConfDepth is the number of blocks the nursery store waits before
	// determining outputs in the chain as confirmed.
	ConfDepth uint32

	// FetchClosedChannels provides access to a user's channels, such that
	// they can be marked fully closed after incubation has concluded.
	FetchClosedChannels func(pendingOnly bool) (
		[]*channeldb.ChannelCloseSummary, error)

	// FetchClosedChannel provides access to the close summary to extract a
	// height hint from.
	FetchClosedChannel func(chanID *wire.OutPoint) (
		*channeldb.ChannelCloseSummary, error)

	// Notifier provides the utxo nursery the ability to subscribe to
	// transaction confirmation events, which advance outputs through their
	// persistence state transitions.
	Notifier chainntnfs.ChainNotifier

	// PublishTransaction facilitates the process of broadcasting a signed
	// transaction to the appropriate network.
	PublishTransaction func(*wire.MsgTx) error

	// Store provides access to and modification of the persistent state
	// maintained about the utxo nursery's incubating outputs.
	Store NurseryStore

	// Sweep sweeps an input back to the wallet.
	SweepInput func(input.Input, sweep.FeePreference) (chan sweep.Result, error)
}

type NurseryStore interface {
	// Incubate registers a set of CSV delayed outputs (incoming HTLC's on
	// our commitment transaction, or a commitment output), and a slice of
	// outgoing htlc outputs to be swept back into the user's wallet. The
	// event is persisted to disk, such that the nursery can resume the
	// incubation process after a potential crash.
	Incubate([]kidOutput, []babyOutput) error

	// CribToKinder atomically moves a babyOutput in the crib bucket to the
	// kindergarten bucket. Baby outputs are outgoing HTLC's which require
	// us to go to the second-layer to claim. The now mature kidOutput
	// contained in the babyOutput will be stored as it waits out the
	// kidOutput's CSV delay.
	CribToKinder(*babyOutput) error

	// PreschoolToKinder atomically moves a kidOutput from the preschool
	// bucket to the kindergarten bucket. This transition should be executed
	// after receiving confirmation of the preschool output. Incoming HTLC's
	// we need to go to the second-layer to claim, and also our commitment
	// outputs fall into this class.
	//
	// An additional parameter specifies the last graduated height. This is
	// used in case of late registration. It schedules the output for sweep
	// at the next epoch even though it has already expired earlier.
	PreschoolToKinder(kid *kidOutput, lastGradHeight uint32) error

	// GraduateKinder atomically moves an output at the provided height into
	// the graduated status. This involves removing the kindergarten entries
	// from both the height and channel indexes. The height bucket will be
	// opportunistically pruned from the height index as outputs are
	// removed.
	GraduateKinder(height uint32, output *kidOutput) error

	// FetchPreschools returns a list of all outputs currently stored in
	// the preschool bucket.
	FetchPreschools() ([]kidOutput, error)

	// FetchClass returns a list of kindergarten and crib outputs whose
	// timelocks expire at the given height.
	FetchClass(height uint32) ([]kidOutput, []babyOutput, error)

	// HeightsBelowOrEqual returns the lowest non-empty heights in the
	// height index, that exist at or below the provided upper bound.
	HeightsBelowOrEqual(height uint32) ([]uint32, error)

	// ForChanOutputs iterates over all outputs being incubated for a
	// particular channel point. This method accepts a callback that allows
	// the caller to process each key-value pair. The key will be a prefixed
	// outpoint, and the value will be the serialized bytes for an output,
	// whose type should be inferred from the key's prefix.
	ForChanOutputs(*wire.OutPoint, func([]byte, []byte) error) error

	// ListChannels returns all channels the nursery is currently tracking.
	ListChannels() ([]wire.OutPoint, error)

	// IsMatureChannel determines the whether or not all of the outputs in a
	// particular channel bucket have been marked as graduated.
	IsMatureChannel(*wire.OutPoint) (bool, error)

	// RemoveChannel channel erases all entries from the channel bucket for
	// the provided channel point, this method should only be called if
	// IsMatureChannel indicates the channel is ready for removal.
	RemoveChannel(*wire.OutPoint) error
}

type RetributionStore interface {
	// Add persists the retributionInfo to disk, using the information's
	// chanPoint as the key. This method should overwrite any existing
	// entries found under the same key, and an error should be raised if
	// the addition fails.
	Add(retInfo *retributionInfo) error

	// IsBreached queries the retribution store to see if the breach arbiter
	// is aware of any breaches for the provided channel point.
	IsBreached(chanPoint *wire.OutPoint) (bool, error)

	// Finalize persists the finalized justice transaction for a particular
	// channel.
	Finalize(chanPoint *wire.OutPoint, finalTx *wire.MsgTx) error

	// GetFinalizedTxn loads the finalized justice transaction, if any, from
	// the retribution store. The finalized transaction will be nil if
	// Finalize has not yet been called for this channel point.
	GetFinalizedTxn(chanPoint *wire.OutPoint) (*wire.MsgTx, error)

	// Remove deletes the retributionInfo from disk, if any exists, under
	// the given key. An error should be re raised if the removal fails.
	Remove(key *wire.OutPoint) error

	// ForAll iterates over the existing on-disk contents and applies a
	// chosen, read-only callback to each. This method should ensure that it
	// immediately propagate any errors generated by the callback.
	ForAll(cb func(*retributionInfo) error) error
}

type WalletUnlockParams struct {
	// Password is the public and private wallet passphrase.
	Password []byte

	// Birthday specifies the approximate time that this wallet was created.
	// This is used to bound any rescans on startup.
	Birthday time.Time

	// RecoveryWindow specifies the address lookahead when entering recovery
	// mode. A recovery will be attempted if this value is non-zero.
	RecoveryWindow uint32

	// Wallet is the loaded and unlocked Wallet. This is returned
	// from the unlocker service to avoid it being unlocked twice (once in
	// the unlocker service to check if the password is correct and again
	// later when lnd actually uses it). Because unlocking involves scrypt
	// which is resource intensive, we want to avoid doing it twice.
	Wallet *wallet.Wallet

	// ChansToRestore a set of static channel backups that should be
	// restored before the main server instance starts up.
	ChansToRestore walletunlocker.ChannelsToRecover
}